Ascend Archive
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(ASCEND) DNS Resolution Bug
I'm confused by this response. If virtually nobody else supports
the TCP part of the RFC, and that's required for DNS responses of
over 512 bytes -- why is it that this ONLY fails on our ascend
equipment, and not on our unix machines or cisco routers?
Mike Berger
Shouting Ground Technologies, Inc.
> ------------------------------
>
> From: "Kevin A. Smith" <kevin@ascend.com>
> Date: Mon, 11 May 1998 11:34:29 -0700
> Subject: Re: (ASCEND) DNS resolution bug
>
> At 09:27 AM 5/8/98 -0700, Kit Knox wrote:
> >
> >There appears to be a problem with Ascend's DNS resolution code and hosts
> >with many A records. Could people with a minute to spare please do the
> >following :
> >
>
> The problem is an old one that has just surfaced on our products. It's
> been around as Kit observes on other (including UNIX) platforms for a
> while. It relates to a section of the relevant RFC - where DNS replies
> of over 512 bytes is addressed.
>
> Conclusion so far...
>
> DNS is normally a UDP based protocol, however if the reply is longer than
> 512 bytes, the RFC recommends establishing a TCP connection. This is not a
> widely implemented portion of the RFC, as few DNS lookups require more than
> 512 byte responses.
>
> We have considered processing what we could (the first 512 bytes) and
> ignoring the TC bit. But that could have unpredictable consequences.
> The alternative is also unpredictable, since virtually no one else supports
> the TCP option, even if we did, it most likely wouldn't work.
>
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